Parallel Two-Electron Reduced Density Matrix Based Electronic Structure Software for Highly Correlated Molecules and Materials

The variational two-electron reduced-density matrix (v2RDM) method provides an effective framework for computer modeling of the electronic structure of complex molecules and materials that exhibit strong correlation effects. In Phase I and Phase II of this STTR we have demonstrated that the GPU-accelerated implementation of the v2RDM-based complete active space self-consistent field (v2RDM-CASSCF) method can treat problems as large as 64 electrons in 64 orbitals on a single workstation, which exceeds by a large margin the capabilities of alternative state-of-the art CASSCF implementations. In this Sequential Phase 2 project, we propose to build upon our success and extend the v2RDM methodology to alternative descriptions of strong electron correlation such as the v2RDM-driven doubly occupied configuration interaction (DOCI) approach, as well as to the treatment of dynamical correlation effects via techniques such as the adiabatic connection (AC) and multiconfigurational pair-density functional theory (MCPDFT). In addition, we propose a number of algorithmic improvements that aim to significantly improve the efficiency of the code.